Mailbox attachment for holding and protecting letters



FIG. 1 is a top plan view of a mailbox attachment for holding and protecting letters showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view, the left side being a mirror image thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a top, right front perspective view thereof drawn to an enlarged scale. 

The ornamental design for a mailbox attachment for holding and protecting letters, as shown and described. 